Method for operating a vehicle on an inclined roadway, electronic vehicle guidance system, and vehicle

Abstract

One aspect of the invention relates to a method for operating a vehicle (1), having the following steps: - moving the vehicle (1) on an inclined roadway (8); - determining the inclination angle (α) of the inclined roadway (8); and - modifying the operating mode of an ultrasound-based surroundings detection system (5) of the vehicle (1) on the basis of the determined inclination angle (α).

Description

[0001] Method for operating a vehicle on a sloping roadway, electronic vehicle guidance system and vehicle

[0002] One aspect of the invention relates to a method for operating a vehicle. Another aspect of the invention relates to an electronic vehicle guidance system. Yet another aspect of the invention relates to a vehicle.

[0003] Today's vehicles are equipped with a wide variety of assistance systems. These are designed to support the driver during semi-autonomous operation. In fully autonomous operation, such assistance systems take complete control of the vehicle.

[0004] A modern vehicle typically also features an environment detection system. This environment detection system can detect the vehicle's surroundings. Based on this information, assistance systems can intervene in the vehicle's steering or completely take over control. Regarding vehicle control, for example, a change in the vehicle's longitudinal dynamics, such as acceleration or braking, is possible. Furthermore, intervention in the vehicle's steering system is also possible. These are just a few examples of how an assistance system can at least support the vehicle's steering or completely take over, depending on the environmental information.

[0005] Due to the extremely diverse environmental scenarios, assistance systems can sometimes operate and assist with great precision, but on the other hand, they may only be used with a certain degree of inaccuracy. Since the safety of driving the vehicle is the absolute top priority when using an assistance system, this must be taken into account.

[0006] It is an object of the present invention to provide a method, an electronic vehicle guidance system and a vehicle in which or with which the operation of a vehicle is improved.

[0007] This object is achieved by a method, an electronic vehicle guidance system, and a vehicle according to the independent claims. One aspect of the invention relates to a method for operating a vehicle, in particular comprising the following steps:

[0008] - Moving the vehicle on a sloping road;

[0009] - Determining an angle of inclination of the sloping roadway;

[0010] - Changing an operating mode of an ultrasonic-based environment detection system of the vehicle depending on the determined inclination angle.

[0011] Such a method improves the vehicle's operation. This approach is particularly advantageous when operation is supported by an electronic assistance system. This is because it allows the vehicle to operate safely with the assistance system. In very specific driving situations, such as downhill driving, the vehicle's operation and thus the use of an assistance system should be improved, and in particular, made safer. For example, it makes it possible for an assistance system that also intervenes in the vehicle's braking system to be improved during such driving on a downhill road. This makes it easier to avoid undesired braking maneuvers.In this context, it is also advantageous that such driving on a downhill road is detected, specifically by determining the angle of inclination of the road. This particularly advantageously enables the method to precisely detect this angle of inclination and, based on this information, to change the active operating mode of a very specific electronic system of the vehicle, namely the ultrasound-based environment detection system, from one active operating mode to another. This also ensures that a change in operating mode does not occur across the board on even a slightly inclined road. This could be counterproductive in this context and, in turn, result in the operation of an assistance system that operates on the basis of the information acquired by the environment detection system.Therefore, the method particularly advantageously enables downhill roadways with a greater angle of inclination to be detected and differentiated from lesser inclinations. Precisely this detailed information is then a key influencing parameter for deciding whether or not to change the operating mode of this specific ultrasound-based environment detection system. This also enables such a change in the operating mode of the ultrasound-based environment detection system, particularly in the case of greater inclinations of the downhill roadway and thus a greater angle of inclination. The ultrasound-based environment detection system can thus be operated in a particularly intelligent manner in at least two different active operating modes, depending on a greater or lesser angle of inclination.A key aspect of the concept is that such an ultrasound-based environment detection system fundamentally has at least two different active operating modes, i.e., modes in which active detection is also performed. These modes can then be changed depending on a specific driving situation, namely driving on a downhill road with a correspondingly greater inclination angle. This allows the adapted and better operating mode of the ultrasound-based environment detection system for detecting the environment to be used, depending on the gradient of the downhill road. This also ensures that environment detection is improved and more accurate, especially during such specific driving situations on downhill roads.The environmental information thus obtained is therefore more meaningful and precise, which also improves and makes the operation of an electronic assistance system in the vehicle dependent on it safer.

[0012] In one embodiment, the inclination angle is determined based on information from at least one acceleration sensor of the vehicle. Additionally, or instead of this, the inclination angle can be determined based on information from at least one wheel speed sensor of the vehicle. This specific information from these very specific sensors makes it possible to determine the inclination angle very precisely. This also creates an improved information base for changing the operating mode more accurately as needed.

[0013] In this context, it is advantageous for sensors of a vehicle's ABS (anti-lock braking system), for example, to record a value that includes both the force of gravity and the vehicle's own acceleration when driving on a downhill road. A wheel speed sensor, in contrast, can determine the vehicle's acceleration itself. Thus, the angle of inclination of the road can be determined from these two pieces of information, particularly based on a motion model. In particular, the weight force g is also taken into account here.

[0014] This allows the angle of inclination to be determined quickly and dynamically. This ensures that the angle of inclination can always be determined correctly, even when the vehicle is moving dynamically. This allows for a very precise determination of whether and, if so, when the operating mode of this ultrasound-based environment detection system should be changed.

[0015] In one embodiment, an actual tilt angle is determined and compared with a threshold tilt angle. The threshold tilt angle is, in particular, the one that initiates a change in the operating mode of the ultrasound-based environment detection system. This also means that if the tilt angle is smaller than the threshold tilt angle, the ultrasound-based environment detection system is operated in a first operating mode. If the actual tilt angle is greater than the threshold tilt angle, the ultrasound-based environment detection system is operated in a second operating mode. These operating modes are different.

[0016] The threshold inclination angle is preferably between 6° and 8°, in particular 7°. In particular, the first operating mode is set when the inclination angle is less than or equal to 7°. The second operating mode is set when the inclination angle is greater than 7°. In one exemplary embodiment, the environment detection system is designed based on ultrasonic signals to determine a height of an object in the environment of the vehicle. In particular, a change in the operating mode of this ultrasound-based environment detection system changes a related height determination. This also means that the operating modes have different types or methods or procedures for determining such a height of such an object. The ultrasound-based environment detection system has a plurality of ultrasonic sensors. These are arranged in particular on the vehicle.

[0017] This is a very advantageous embodiment, since this height determination can be distorted, especially when driving on downhill roads. Especially when, for example, an object in the surrounding area is located at the end of the downhill road in an area where the downhill road transitions back into a less steep road or a horizontal road, or when this object is already located in the direction of travel of the vehicle at the beginning of this less steep or horizontal road section that follows the downhill road, height determination can be subject to greater inaccuracy. This is particularly the case when the ultrasound-based environment detection system has several, in particular at least two different operating modes, in order to be able to perform such a height determination of an object in the surrounding area.This is because it is then possible that, for example, one operating method or operating mode of such an altitude determination works better in a first type of environmental scenario and thus delivers more accurate results than the other operating method or operating mode, which in turn delivers more accurate altitude determination results in other different environmental scenarios compared to the first operating mode.

[0018] Therefore, it is particularly advantageous in this context to provide such an improved environment detection system with at least two different operating modes for determining the height of an object in the environment. Based on this, the proposed method then enables these different operating modes to be used in a particularly advantageous manner depending on the situation. In the overall context, this particularly advantageously achieves the best and therefore most accurate height determination as needed, both with regard to height determination and with regard to a respective individual traffic situation or environmental scenario. This, in turn, results in an assistance system that operates on the basis of the information generated by the environment detection system being improved even in the most diverse environmental scenarios.This can, for example, prevent unwanted braking maneuvers when driving along such a downhill road. This could occur if, at a specific road gradient, the height of an object is determined using an operating mode that is less accurate in the specific environmental situation. For example, if an object that is located in front of the vehicle in the direction of travel but is already on the roadway adjacent to the downhill road is detected and incorrectly identified as a high object, and the assistance system initiates a braking maneuver.By changing to the other operating mode or the other operating mode in such constellations or by using this in the focus for determining the height of the object and determining the height more correctly or accurately for this traffic situation, unnecessary or even incorrect braking can be avoided.

[0019] In one embodiment, the environment detection system has a first

[0020] Method for determining the height of an object. In particular, it has at least a second method for determining the height of an object, which is different from the first method. A change in the operating mode for determining the height is carried out by switching from one method to the other method. In particular, in such an embodiment, it can be provided that only one of the two methods is ever used for determining the height. Thus, in such a case, a discrete distinction is always made between one method and the other method, and only one of these methods is ever used for determining the height.

[0021] In another exemplary embodiment, it is possible that, given such a plurality of, in particular two, different methods for determining the height of an object, both methods are used to determine the height based on a priority list. In such a case, the operating mode for determining the height can be changed so that both methods are again used, but the order of priority in the priority list is changed. Thus, in such an exemplary embodiment, it is also possible to perform the height determination redundantly, but always taking this priority list into account. Based on this priority list, a result provided by a method with a higher ranking in the priority list is classified as having greater confidentiality than the result from a method with a lower priority in the priority list.This approach thus provides a concept in which both altitude determination methods are used, at least in different situations. However, the confidence level is determined individually depending on the environmental situation, particularly with regard to driving on a downhill road. This is achieved, in particular, by sorting or reordering the methods accordingly in the priority list.

[0022] In one embodiment, the two methods for determining the height differ in the type of signal evaluation of the ultrasonic signals and / or in the type of information used for the evaluation and / or in the accuracy of the evaluation result for different environmental scenarios.

[0023] In particular, it is provided that in one exemplary embodiment, the ultrasonic detection system has at least one ultrasonic sensor, in particular a plurality of ultrasonic sensors, which can transmit on at least two different channels. In particular, these channels are such that their main radiation directions of the ultrasonic signal are oriented in the same way. However, with regard to the different channels, different ultrasonic signals are emitted, which have at least different sound lobes. Such an example of a first method makes it possible, in particular if the sound lobe of the low channel is significantly narrower than the sound lobe of the high channel. In particular, such a concept, in which these sound lobes are significantly different, can achieve improved determination of the precise height of an object even over a greater range.In particular, this also enables a much more precise distinction between a tall and a short object. In this context, a tall object is defined as one that is higher than a value between 20 cm and 30 cm. However, it is precisely in such situations that, when driving downhill with a specific gradient on a sloping road, a situation can arise based on this determination method, which can be referred to as the amplitude comparison method, in which an otherwise low object is detected as tall. It is precisely in such situations that the assistance system would then initiate a braking maneuver. The scenario described above is particularly advantageous to prevent this from happening.In this context, when driving on a downhill road, particularly with a greater angle of inclination, this first method is not used to determine the height of the object or is not used as the first priority method, but is then switched to the other operating mode in which the second method is used to determine the height or is at least used as the first priority method, such an object is correctly recognized as low and thus an incorrect braking maneuver is avoided.

[0024] This is particularly advantageous, for example, when driving on a downhill roadway where, at the transition to a flatter section of roadway that is less inclined than the downhill section, a low speed bump is positioned as an object that must be driven over. This can be the case, for example, in parking garages to avoid driving too fast when driving between two levels at the end of the downhill section. Therefore, such bump-like elevations are advantageous at these specific locations, allowing the driver to enter this area at a controlled and adjusted speed.

[0025] In contrast to the described evaluation using the amplitude comparison method, the second method can be based on a different procedure based on the aforementioned parameters. In particular, different methods for evaluating the received echo signals of the ultrasonic signals can be considered. In one exemplary embodiment, a change in the operating mode occurs when, after the end of the downhill roadway, a raised object is located on a roadway adjoining the downhill roadway, which is horizontal or has a lower incline than the downhill roadway. Such a raised object can be the hump element mentioned above.

[0026] A further aspect of the invention relates to an electronic vehicle guidance system. The vehicle guidance system has at least one evaluation unit. The electronic vehicle guidance system is designed to carry out driving according to one of the preceding claims or an advantageous embodiment thereof. In particular, the method is carried out with the electronic vehicle guidance system. The electronic vehicle guidance system can also have an electronic assistance system. In particular, it can also control a braking system and / or steering system of the vehicle. In particular, this occurs at least depending on the environmental information acquired with the ultrasound-based environment detection system.

[0027] A further aspect of the invention relates to a vehicle with an electronic vehicle guidance system according to the above-mentioned aspect or an advantageous embodiment thereof.

[0028] Embodiments of the invention are explained in more detail below with reference to schematic drawings. They show:

[0029] Fig. 1 shows a schematic traffic situation or an environmental scenario in which an embodiment of a vehicle according to the invention, which has an embodiment of an electronic vehicle guidance system according to the invention, is traveling on a downhill road; and

[0030] Fig. 2 is a schematic representation of a method for determining a height of an object in the surroundings of the vehicle.

[0031] In the figures, identical or functionally equivalent elements are provided with the same reference numerals. Fig. 1 shows a schematic representation of a vehicle 1. The vehicle 1 has an electronic vehicle guidance system 2. The vehicle 1 also has a steering system 3 and a braking system 4. In addition, the vehicle 1 has an environment detection system 5. The environment detection system 5 has a plurality of ultrasonic sensors, of which only two ultrasonic sensors 5a and 5b are shown here for the sake of clarity. The ultrasound-based environment detection system 5 is designed to detect an environment 6 of the vehicle 1. The environment detection system 5 can be a component of the electronic vehicle guidance system 2. The electronic vehicle guidance system 2 has, in particular, an assistance system 7. The assistance system 7 is provided for controlling the steering system 3 and / or the braking system 4.Especially during at least semi-autonomous, in particular fully autonomous, operation of the vehicle 1 during various driving maneuvers, the electronic vehicle guidance system 2, in particular the assistance system 7, can then independently control the steering system 3 and / or the braking system 4. In particular, this is also done based on the information from the environment detection system 5.

[0032] In the illustration according to Fig. 1, the vehicle 1 is traveling on a sloping roadway 8. This is inclined at an angle of inclination α with respect to a horizontal line 9. As can also be seen in Fig. 1, this sloping roadway 8 merges into a further roadway 10 at its front end, seen in the direction of travel of the vehicle 1. This further roadway 10 represents a roadway section which, in comparison to the sloping roadway 8, is inclined less with respect to the horizontal line 9 or is oriented horizontally. Fig. 1 also shows that an object 11 is arranged on this further roadway 10, in particular in a closer position to the sloping roadway 8. In the exemplary embodiment, this raised object 11 is designed with a height which is less than or equal to 20 cm, in particular less than or equal to 15 cm. In particular, the height of the object 11 is, for example, greater than or equal to 10 cm.

[0033] Functionally, this object 11 is arranged in a fixed location and is intended to be permanently located in this position. It can be a sill, which is desired and defined in this position in order to prevent the vehicle 1 from driving too quickly on the downhill lane 8 and then also on the subsequent lane 10. For example, the scenario shown in Fig. 1 can be in a parking garage. The downhill lane 8 can in this context be a connecting section between two levels of the parking garage. The vehicle 1 also has at least one acceleration sensor 12. This can, for example, be part of an ABS system of the vehicle 1. It can thus also be part of the braking system 4. In addition, the vehicle 1 can have at least one wheel speed sensor 13. Both the number and the position of this wheel speed sensor 13 are shown in Fig.1 is by no means intended to be exhaustive, but is merely a symbolic representation. The electronic vehicle guidance system 2 can furthermore have, in particular, an evaluation unit 14. This can be a computing unit and / or a control unit. This evaluation unit 14 can evaluate information from the sensors 12 and / or 13 and / or the environment detection system 5 and / or the steering system 3 and / or the braking system 4. Depending on this, control signals can then be generated, for example, in order to be able to control the steering system 3 and / or the braking system 4.

[0034] Based on the scenario illustrated in Fig. 1, as the vehicle 1 moves along the downhill roadway 8, the angle of inclination a of this downhill roadway 8 is determined. Depending on this angle of inclination a, an operating mode of the ultrasound-based environment detection system 5 of the vehicle 1 is changed. In particular, during this change of operating mode, the method for determining the height of the object 11 located in front of the vehicle 1 in the direction of travel of the vehicle 1 is changed.

[0035] In this context, Fig. 2 shows a schematic representation, which explains a first method for determining the height of an object.

[0036] Basically and independently of the representation in Fig. 2, the environment detection system 5 is configured such that it has at least two different methods for determining the height of an object in the environment of the vehicle 1.

[0037] Fig. 2 explains a first method that works based on an amplitude comparison of ultrasonic signals. In this exemplary embodiment, the ultrasonic sensors 5a and 5b have two different signal channels. One is a low-signal channel and the other is a high-signal channel. The high-signal channel emits an ultrasonic signal 15 that has a significantly narrower sound cone than another ultrasonic signal 16 emitted by the low-signal channel. As can be seen in Fig. 2, both signal channels have the same main radiation direction H. This main radiation direction H is oriented horizontally here, for example. If these two signals are emitted, especially in quick succession, reflected signals and thus echo signals are received in the case of a tall object, which have essentially the same amplitude or have the same amplitude within a small tolerance range.By comparing these two amplitudes and thus determining the magnitude of the amplitudes, it can be concluded that the detected object is tall. This means that it has a height greater than a certain threshold. This threshold could be, for example, 20 cm, but this is not intended to be exhaustive or necessarily restrictive.

[0038] However, if with this method only a low object is present, as can be seen in Fig. 2, the reflected signals and thus the received echo signals will differ significantly in their amplitudes. As can be seen in the illustration in Fig. 2, with the low object 18 only the amplitude of the ultrasonic signal 16 in the echo signal is large, whereas in comparison the amplitude of the echo signal of the ultrasonic signal 15 is low. Therefore, in this constellation it can again be detected very precisely that this object 18 is low. Through this simple, yet highly precise analysis due to the significant differences in the sound lobes of the ultrasonic signals 15 and 16, this method can also be used for distances between the ultrasonic sensor 5a, 5b and the object 17, 18 of up to more than 2 meters, in particular even 3 meters.

[0039] However, this very advantageous and very precise method for determining height is subject to uncertainty when driving on a sloping roadway 8. In the configuration shown in Fig. 1 in particular, the situation arises that when the ultrasonic signals 15 and 16 are emitted, they hit the object 11 horizontally and thus in the direction of the vehicle's longitudinal axis, as symbolized by the arrow P in Fig. 1, and thus an echo would be reflected for both ultrasonic signals 15 and 16, which would have essentially the same amplitudes and thus, in the configuration shown in Fig. 1, this method of determining height would provide an inaccurate or incorrect result regarding the height of the object 11.

[0040] Therefore, it is advantageous, particularly in the context explained above, if, upon detection of this travel on the sloping roadway 8, in particular with an inclination angle α, the explained first method for determining the height is deviated from, in particular if the inclination angle is greater than 7°, and then the aforementioned second method for determining the height is used. In this regard, it can be provided that, if the inclination angle α is greater than 7°, this first method is not completely deactivated, but rather is no longer the lowest-ranking method in a priority list, but rather the second method is re-sorted as the highest-ranking method, and then the second method is used as the basis for determining the height of the object 11, in particular at least with priority.The first method can then remain activated in one embodiment and, if necessary, also be taken into account, but with regard to the confidentiality of its evaluation result for determining the height, it can be set significantly lower than the result of the height determination of this then higher-ranking, in particular highest-ranking second method.

[0041] When the vehicle 1 is moving dynamically, this determination of the angle of inclination can be performed at discrete time intervals or continuously. This allows for very rapid and dynamic detection, as needed, of whether and when a change in the operating mode of the environment detection system 5 occurs, particularly with regard to the use of a specific method for determining the height of an object 11 in the environment 6 of the vehicle 1.

Claims

Patent claims 1. A method for operating a vehicle (1) comprising the following steps: moving the vehicle (1) on a sloping roadway (8); Determining an inclination angle (a) of the sloping roadway (8); changing an operating mode of an ultrasound-based environment detection system (5) of the vehicle (1) depending on the determined inclination angle (a).

2. Method according to claim 1, wherein the angle of inclination (a) is determined as a function of information from at least one acceleration sensor (12) of the vehicle (1) and as a function of information from at least one wheel speed sensor (13) of the vehicle (1).

3. The method according to claim 1 or 2, wherein a first operating mode is set when the inclination angle (a) is less than a threshold inclination angle, and a second operating mode is set when the inclination angle (a) is greater than or equal to the threshold inclination angle.

4. The method according to claim 3, wherein the threshold inclination angle is specified as a value between 5° and 9°, in particular between 6° and 8°, in particular 7°.

5. Method according to one of the preceding claims, wherein the environment detection system (5) is designed on the basis of ultrasonic signals from ultrasonic sensors (5a, 5b) for determining a height of an object (11) in the environment (6) of the vehicle (1), and a height determination in this regard is changed when the operating mode is changed.

6. The method according to claim 5, wherein the environment detection system (5) has a first method for determining the height of an object (11) and a second method, which is different therefrom, for determining the height of an object (11) and a change in the operating mode for determining the altitude is carried out by switching from one method to the other.

7. The method according to claim 5, wherein the environment detection system (5) has a first method for determining the height of an object (11) and a second method, which is different therefrom, for determining the height of an object (11), and both methods are used for determining the height on the basis of a priority list, and as a change in the operating mode for determining the height, both methods are used but the ranking in the priority list is changed.

8. The method according to claim 6 or 7, wherein the two methods differ in the type of signal evaluation and / or in the type of information used as a basis for the evaluation of the signals and / or in the accuracy of the evaluation result for different environmental scenarios.

9. Method according to one of the preceding claims, wherein a change in the operating mode occurs when a raised object (11) is arranged after the end of the sloping roadway (8) on a further roadway (10) adjoining the sloping roadway (8).

10. Electronic vehicle guidance system (2) with an evaluation unit (14), wherein the electronic vehicle guidance system (2) is designed to carry out a method (1) according to one of the preceding claims.

11. Vehicle (1) with an electronic vehicle guidance system (2) according to claim 9.

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